Created listener interfaces that will automatically be registered

if implemented by something on the display hierarchy.
You may also implement them in utility classes and register and unregister
event listening by hand.


git-svn-id: svn+ssh://src.earth.threerings.net/vilya/trunk@55 c613c5cb-e716-0410-b11b-feb51c14d237

src/as/com/threerings/ezgame/client/EZGamePanel.as

@@ -38,6 +38,7 @@ public class EZGamePanel extends VBox
 
         // add a listener so that we hear about all new children
         addEventListener(Event.ADDED, childAdded);
+        addEventListener(Event.REMOVED, childRemoved);
 
         var cfg :EZGameConfig = (ctrl.getPlaceConfig() as EZGameConfig);
         _gameView = new MediaContainer(cfg.configData); // TODO
@@ -64,6 +65,7 @@ public class EZGamePanel extends VBox
     // from PlaceView
     public function didLeavePlace (plobj :PlaceObject) :void
     {
+        removeListeners(_gameView);
         _ezObj = null;
     }
 
@@ -77,6 +79,17 @@ public class EZGamePanel extends VBox
         }
     }
 
+    /**
+     * Handle REMOVED events.
+     */
+    protected function childRemoved (event :Event) :void
+    {
+        trace("Child removed: " + event.target);
+        if (_ezObj != null) {
+            removeListeners(event.target as DisplayObject);
+        }
+    }
+
     /**
      * Find any children of the specified object that implement
      * com.metasoy.game.Game and provide them with the GameObject.
@@ -93,6 +106,17 @@ public class EZGamePanel extends VBox
                         _seenGames[disp] = true;
                     }
                 }
+                // always check to see if it's a listener
+                _ctrl.gameObjImpl.registerListener(disp);
+            });
+    }
+
+    protected function removeListeners (root :DisplayObject) :void
+    {
+        DisplayUtil.walkDisplayObjects(root,
+            function (disp :DisplayObject) :void
+            {
+                _ctrl.gameObjImpl.unregisterListener(disp);
             });
     }